In August 2005, Malaysian Airlines Boeing 777-2H6ER 9M-MRG suffered an in-flight upset en route from Perth to Kuala Lumpur. A safe landing was made back in Perth. The Australian ATSB concluded that a contributing safety factor was that an anomaly existed in the component software hierarchy that allowed inputs from a known faulty accelerometer to be processed by the air data inertial reference unit (ADIRU) and used by the primary flight computer, autopilot and other aircraft systems. Other safety factors identified were: 1) The software anomaly was not detected in the original testing and certification of the ADIRU; and 2) The aircraft documentation did not provide the flight crew with specific information and action items to assess and respond to the aircraft upset event. (ATSB)